The Supreme Court handed down its decision in U.S. v. Jones yesterday, and the blogosphere is abuzz about the case. (See Margot Kaminski, Paul Ohm, Howard Wasserman, Tom Goldstein, and the terrifyinglyprolificOrinKerr.) The verdict was a clean sweep – 9-0 for Jones – but the case produced three opinions, including a duel between Justices Antonin Scalia and Samuel Alito. Thus far, most privacy and constitutional law thinkers favor Alito’s position. That’s incorrect: Justice Scalia’s opinion is far more privacy protective. Here’s why:

Scalia’s theory is basically Katz (reasonable expectation of privacy) plus trespass. For Scalia, the conduct in Jones – law enforcement attaching a GPS transmitter to Jones’s car, and then tracking its movements – is a search because “The Government physically occupied private property for the purpose of obtaining information.” But, that’s not quite precise enough: the key is that the government must “physically intrud[e] on a constitutionally protected area.” (emphasis mine) The tricky part, naturally, is deciding what counts as such an area. Scalia disposes of Oliver (the open fields case) by emphasizing that a field “is not one of those protected areas enumerated in the Fourth Amendment.” Katz is still around for “Situations involving merely the transmission of electronic signals without trespass.”

Scalia thus wants to create magic places: spots where any governmental intrusion, with any physicality, is a search. The home is certainly such a place (see Kyllo) – Jane Yakowitz pointed out to me that this has to explain why the Court took cert in Florida v. Jardines, when we already have Caballes and Place on the books. Determining which places are magic is hard. It’s here that Scalia’s originalism does its work: Scalia wants to apply the understanding and expectations from 1791 to sort places into protected/magic and unprotected.

Alito thinks this is rubbish: his footnote 3 openly makes fun of Scalia’s contention that we can analogize the Jones facts to a constable hiding in a coach (“this would have required either a gigantic coach, a very tiny constable, or both”). His method would instead simply apply the Katz reasonable expectation of privacy test, which he rightly points out is more consonant with the Court’s jurisprudence since its rejection of the physical trespass test set out in Olmstead. This approach looks analytically cleaner, although Alito forthrightly acknowledges the circularity inherent in the reasonable expectations test – expectations derive from the law, in addition to driving it. And, of course, there is the one-way ratchet worry: the government can reduce our reasonable expectations of privacy by abusing our privacy.

Alito, though, proceeds to mess up a previously tidy picture by inventing two new considerations for Fourth Amendment analysis: the duration of the information-gathering (such as GPS tracking), and the severity of the crime. Scalia rightly smacks Alito around for this, as he fails to ground this analysis in anything remotely resembling precedent. At best, this is judicial activism, and at worst, it’s an invitation for a wave of new cases where the government tests boundaries and magnifies the threat posed by those surveilled.

I like Scalia’s approach much better. It sets out clearly that there are some spaces that get heightened privacy protection: we don’t have to engage in the weighing involved in the reasonable expectations test, so it’s cheaper, and there won’t be instances where judges decide that in fact society is willing to permit certain observations in the home, for example. Scalia’s approach is a firewall: it offers a redoubt for privacy. And, it maintains the viability of Katz in other instances. Alito’s two additional considerations point towards the worry that makes me prefer Scalia. Imagine observation of the interior of a home – say, using tiny drones – that would clearly constitute a search under the magic places theory. If the observation is fairly short, or if the crime involved is serious (drug smuggling, terrorism, child pornography), Alito’s analysis would find that there isn’t a search, and hence no need for a warrant. Scalia’s approach always forces the cops to get a warrant. That reassures me.

There are two issues that neither Alito nor Scalia deals with, although to her credit Justice Sonia Sotomayor tackles both: pervasive surveillance, and cloud computing. Pervasive surveillance involves the government’s increasing capabilities to deploy low-cost observation technology – everything from traffic cameras to facial recognition technology – and to store, index, and analyze the resulting torrent of data. Cloud computing involves the shift from maintaining information on devices we control to storing it on devices controlled by Google or Apple or Amazon. The former presents the mosaic theory that the D.C. Circuit endorsed in its opinion in Jones. The latter invites us to re-visit the third party doctrine, whereby one loses any reasonable expectation of privacy if one turns over data to someone else (unless that someone is, say, a priest or lawyer). One failing of the two major opinions in Jones is that they fail to provide any guide for how the Court thinks about these issues – other than to hope mightily that Congress will take care of it for them.

I like Scalia’s hybrid with its magic places. What our privacy rights are when we venture outside the castle walls is a topic the court reserves for another day.